12v Supply - putting a new one in

I am planning to put a new 12v supply into our Mercedes PVC to power the reversing camera, sat nav, dash cam & passenger LED reading light. I'm aiming to source directly from the battery with an inline fuse. Would I need a voltage regulator and spike suppressor? If so, where can I get one?

all of those are designed to work from a cigarette lighter socket so should be designed to take the voltage the alternator will produce but if you want to be double sure voltage regulaters are available from ebay youll have to total up the load to pick the correct ampage
remember to fuse everything